WEST LONGITUDE: THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL STORM ISELLE, LOCATED MORE THAN A THOUSAND MILES WEST-SOUTHWEST OF THE SOUTHERN TIP OF THE BAJA CALIFORNIA PENINSULA. A TROPICAL WAVE IS PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS SEVERAL HUNDRED MILES SOUTH-SOUTHWEST OF MANZANILLO, MEXICO. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR GRADUAL DEVELOPMENT OF THIS SYSTEM DURING THE NEXT SEVERAL DAYS WHILE IT MOVES WESTWARD AT 10 MPH. FORMATION CHANCE THROUGH 48 HOURS... MEDIUM...30 PERCENT. FORMATION CHANCE THROUGH 5 DAYS...HIGH ...70 PERCENT. AN AREA OF LOW PRESSURE LOCATED ABOUT 1275 MILES EAST- SOUTHEAST OF THE BIG ISLAND OF HAWAII IS PRODUCING MINIMAL SHOWER ACTIVITY. UPPER- LEVEL WINDS ARE CURRENTLY NOT CONDUCIVE FOR DEVELOPMENT, BUT THEY COULD BECOME A LITTLE MORE FAVORABLE IN A FEW DAYS WHILE THE LOW MOVES WESTWARD AT AROUND 10 MPH. FORMATION